Acidizing retarder compositions and methods of using the same

ABSTRACT

This disclosure relates to acidizing retarder compositions and methods of reducing the rate of carbonate dissolution in carbonate acidizing treatments of carbonate formations using the acidizing retarder compositions. The methods may include dissolving one or more retarder compounds in a solution comprising a strong acid to form acidizing retarder compositions, and introducing the acidizing retarder compositions to carbonate formations. The acidizing retarder compositions may include one or more retarder compounds and a strong acid. At least one of the one or more retarder compounds may be a poloxamer. A concentration of the strong acid in the acidizing retarder composition may be 5 weight percent or greater.

FIELD

Embodiments disclosed herein generally relate to acidizing retardercompositions and treating a subterranean formation to increasehydrocarbon production.

TECHNICAL BACKGROUND

Acid stimulation is a cost effective, chemical-based well stimulationtreatment method that may be used to create wormholes or conductivefractures in a subterranean formation, enhancing hydrocarbon productionfrom the subterranean formation. Among common acids, hydrochloric acid(HCl) is widely used in acidizing treatments due to its high dissolvingpower, high availability, and low cost. However, a reaction betweenstrong acids, such as HCl, and the subterranean formation may result inpremature acid consumption and depletion near the surface of thesubterranean formation, leading to inefficient stimulation.

SUMMARY

Acidizing retarder compositions may reduce the reactivity of the acidwhen compared to conventional acid treatments. Such reduced reactivityallows subsequent portions of the acid treatments to be diverted awayfrom areas of the subterranean formation that have already been treatedand allows for deeper and more complete treatment of the formation.Consequently, the reduced acid reactivity may allow for deeperpenetration and increased conductivity throughout the length ofwormholes and fractures, which may be induced during the treatment.Thus, compositions and methods to reduce the reaction rate between acidsand subterranean formations, while maintaining the acidizing capabilityof strong acids is highly desired.

These needs are met by the embodiments disclosed herein. One or moreembodiments disclosed herein provide a method of reducing a rate ofcarbonate dissolution in a carbonate acidizing treatment of a carbonateformation comprising dissolving one or more retarder compounds in asolution comprising a strong acid to form an acidizing retardercomposition and introducing the acidizing retarder composition to thecarbonate formation, wherein at least one of the one or more retardercompounds comprises a poloxamer.

According to aspects, an acidizing retarder composition comprises one ormore retarder compounds and a strong acid, wherein at least one of theone or more retarder compounds is a poloxamer, and wherein aconcentration of the strong acid in the acidizing retarder compositionis 5 weight percent or greater.

This summary is provided to introduce a selection of concepts that arefurther described in the detailed description. This summary is notintended to identify key or essential features of the claimed subjectmatter, nor is it intended to be used as an aid in limiting the scope ofthe claimed subject matter.

Additional features and advantages of the described embodiments will beset forth in the detailed description that follows. The additionalfeatures and advantages of the described embodiments will be, in part,readily apparent to those skilled in the art from that description orrecognized by practicing the described embodiments, including thedetailed description that follows as well as the drawings and theclaims.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of acidizingretarder compositions and methods for treating a subterranean formationwith acidizing retarder compositions.

Embodiments disclosed herein include acidizing retarder compositions andmethods of using. More specifically, some embodiments disclosed hereinare directed toward acidizing retarder compositions, and methods ofreducing a rate of carbonate dissolution in a carbonate acidizingtreatment of a carbonate formation using said acidizing carbonatedretarder compositions. In one or more embodiments, an acidizing retardercomposition comprising a retarder compound and a strong acid may becombined with carbonate, which may significantly reduce the dissolutionrate of carbonate, improve the acid stimulation efficiency, and reducethe amount of acid required for stimulation, therefore optimizing theeconomics of hydrocarbon extraction.

In one or more embodiments, an acidizing retarder composition includesone or more retarder compounds and a strong acid. In one or moreembodiments, at least one of the one or more retarder compounds maycomprise a poloxamer. In one or more embodiments, a concentration of thestrong acid in the acidizing retarder composition may be 5 weightpercent or greater.

In one or more embodiments, a method of reducing a rate of carbonatedissolution in a carbonate acidizing treatment of a carbonate formationincludes dissolving one or more retarder compounds in a solutioncomprising a strong acid to form an acidizing retarder composition andintroducing the acidizing retarder composition to the carbonateformation. In one or more embodiments, at least one of the one or moreretarder compounds may comprise a poloxamer.

As used throughout this disclosure, the term “carbonate acidizingtreatment” refers to the treatment of a subterranean formation with astimulation fluid containing a reactive acid. In carbonate formations,the acid dissolves the entire formation matrix. The carbonate acidizingtreatment improves the formation permeability to enable enhancedproduction of reservoir fluids. Carbonate acidizing operations areideally performed at pressures below the fracture pressure of theformation. This enables the acid to penetrate the formation and extendthe depth of treatment while avoiding damage to the reservoir formation.

As used throughout this disclosure, the term “carbonate” refers to aclass of sedimentary rock that comprises 95% or more by weight calcite(CaCO₃), aragonite (also CaCO₃), and dolomite (CaMg(CO₃)₂). Dolomite isa mineral that can replace calcite during the process of dolomitization.Limestone, dolostone or dolomite, and chalk are carbonate rocks.Carbonate rocks can serve as hydrocarbon reservoir rocks, particularlyif their porosity has been enhanced through dissolution. Wormholes andfractures augment permeability of subterranean formations to allow forflow and extraction of hydrocarbon reservoirs trapped within thereservoir rocks.

As used throughout this disclosure, the term “formation matrix” refersto the finer grained, interstitial particles that lie between largerparticles or in which larger particles are embedded in sedimentary rockssuch as sandstones and conglomerates.

As used throughout this disclosure, the term “reservoir” refers to asubsurface formation having sufficient porosity and permeability tostore and transmit fluids.

As used throughout this disclosure, the term “subterranean formation”refers to a body of rock that is sufficiently distinctive and continuousfrom the surrounding rock bodies such that the body of rock can bemapped as a distinct entity. A subterranean formation is, therefore,sufficiently homogenous to form a single identifiable unit containingsimilar properties throughout the subterranean formation, including, butnot limited to, porosity and permeability. A subterranean formation isthe fundamental unit of lithostratigraphy.

As used throughout this disclosure, the term “wellbore” refers to thedrilled hole or borehole, including the openhole or uncased portion ofthe well. Borehole may refer to the inside diameter of the wellbore wallor the rock face that bounds the drilled hole.

As used herein, the term “retarder compound” may refer to a chemicalcompound, mixture, or composition operable to reduce a rate of areaction. An acidizing retarder composition may be operable to reducethe rate at which an acid dissolves a material, such as a carbonateformation.

As used herein, the term “acidizing retarder composition” may refer to acomposition operable to dissolve carbonate by reacting an acid with thecarbonate in a reaction in the presence of an additive, where thereaction proceeds at a rate slower than a composition in the absence ofthe additive.

As used herein, the term “strong acid” may refer to an acid solutionwith a pH from 0 to 3. For example, strong acids include, but are notlimited to, hydrochloric acid, nitric acid, sulfuric acid, hydrobromicacid, hydroiodic acid, triflic acid, perchloric acid, or a combinationof two or more thereof. The strong acid may include mineral acids,organic acids, or combinations thereof.

As used herein, the term “fluid” may include liquids, gases, or both.

As used throughout this disclosure, the term “production tubing” refersto a wellbore tubular used to produce reservoir fluids. Productiontubing is assembled with other completion components to make up theproduction string. The production tubing selected for any productionstring should be compatible with the wellbore geometry, reservoirproduction characteristics, and the reservoir fluids.

As used throughout this disclosure, the term “coiled tubing” refers to along, continuous length of pipe wound on a spool. The pipe isstraightened prior to pushing into a wellbore and rewound to coil thepipe back onto the transport and storage spool. It will be appreciatedthat coiled tubing may be 5,000 meters (m) or greater in length. Coiledtubing may be provided as a secondary and separated conduit through thewellbore and may be passed within the annulus of the production tubing.

In one or more embodiments, the acidizing retarder composition comprisesone or more retarder compounds. In one or more embodiments, at least oneof the one or more retarder compounds is a poloxamer. As used herein,the term “poloxamer” may refer to a triblock copolymer comprising acentral hydrophobic chain of poly(propylene oxide) and two hydrophilicchains of poly(ethylene oxide).

In one or more embodiments, the poloxamer may comprise a structure offormula (I):

in which x, y, and z are each independently an integer that indicate anumber of repeat units present in the compound. Without being bound byany particular theory, it is believed that the triblock structurecomprising the central hydrophobic chain and two hydrophilic chains ofthe poloxamer may result in a water soluble compound that may bedissolved in an acid solution to form the acidizing retardercomposition.

In one or more embodiments, x and z each may independently be an integerfrom 50 to 150, For instance, in one or more embodiments, x and z eachmay independently be an integer from 50 to 100, from 55 to 100, from 60to 100, from 65 to 100, from 70 to 100, from 75 to 100, from 80 to 100,from 85 to 100, from 90 to 100, from 95 to 100, from 50 to 105, from 55to 105, from 60 to 105, from 55 to 105, from 70 to 105, from 75 to 105,from 80 to 105, from 85 to 105, from 90 to 105, from 95 to 105, from 50to 110, from 55 to 110, from 60 to 110, from 65 to 110, from 70 to 110,from 75 to 110, from 80 to 110, from 85 to 110, from 90 to 110, from 95to 110, from 50 to 120, from 55 to 120, from 60 to 120, from 65 to 120,from 70 to 120, from 75 to 120, from 80 to 120, from 85 to 120, from 90to 120, from 95 to 120, from 50 to 130, from 55 to 130, from 60 to 130,from 65 to 130, from 70 to 130, from 75 to 130, from 80 to 130, from 85to 130, from 90 to 130, from 95 to 130, from 50 to 140, from 55 to 140,from 60 to 140, from 65 to 140, from 70 to 140, from 75 to 140, from 80to 140, from 85 to 140, from 90 to 140, from 95 to 140, from 50 to 150,from 55 to 150, from 60 to 150, from 65 to 150, from 70 to 150, from 75to 150, from 80 to 150, from 85 to 150, from 90 to 150, from 95 to 150,from 98 to 102, or from 100 to 102.

In one or more embodiments, y may be an integer from 20 to 80. Forinstance, in one or more embodiments, y may be an integer from 20 to 80,from 25 to 80, from 30 to 80, from 35 to 80, from 40 to 80, from 45 to80, from 50 to 80, from 55 to 80, from 20 to 70, from 25 to 70, from 30to 70, from 35 to 70, from 40 to 70, from 45 to 70, from 50 to 70, from55 to 70, from 20 to 60, from 25 to 60, from 30 to 60, from 35 to 60,from 40 to 60, from 45 to 60, from 50 to 60, or from 55 to 60.

In one or more embodiments, the poloxamer may comprise Poloxamer 407, atriblock copolymer comprising a central hydrophobic block ofpolypropylene glycol with an average block length of 56 repeat unitspositioned between two hydrophilic blocks of polyethylene glycol,wherein each of the two hydrophilic blocks of polyethylene glycol havean average block length of 101 repeat units. An exemplary compoundcomprising Poloxamer 407 is Pluronic™ F-127, a commercially availablematerial from BASF.

In one or more embodiments, the acidizing retarder composition maycomprise from 0.01 weight percent (wt. %) to 5 wt. % of the one or moreretarder compounds based on the total weight of the acidizing retardercomposition. For instance, the acidizing retarder composition maycomprise from 0.01 wt. % to 0.1 wt. %, from 0.01 wt. % to 0.5 wt. %,from 0.1 wt. % to 0.5 wt. %, from 0.01 wt. % to 1 wt. %, from 0.1 wt. %to 1.0 wt. %, from 0.5 wt. % to 1 wt. %, from 0.01 wt. % to 2 wt. %,from 0.1 wt. % to 2 wt. %, from 0.5 wt. % to 2 wt. %, from 1 wt. % to 2wt. %, from 0.01 wt. % to 3 wt. %, from 0.1 wt. % to 3 wt. %, from 0.5wt. % to 3 wt. %, from 1 wt. % to 3 wt. %, from 2 wt. % to 3 wt. %, from0.01 wt. % to 4 wt. %, from 0.1 wt. % to 4 wt. %, from 0.5 wt. % to 4wt. %, from 1 wt. % to 4 wt. %, from 2 wt. % to 4 wt. %, from 3 wt. % to4 wt. %, from 0.01 wt. % to 5 wt. %, from 0.1 wt. % to 5 wt. %, from 0.5wt. % to 5 wt. %, from 1 wt. % to 5 wt. %, from 2 wt. % to 5 wt. %, from3 wt. % to 5 wt. %, or from 4 wt. % to 5 wt. % of the one or moreretarder compounds based on the total weight of the acidizing retardercomposition. Without intending to be bound by any particular theory, itis believed that a concentration of the one or more retarder compoundsbelow 0.01 wt. % may result in insufficient reduction of the carbonatedissolution rate. Further, it is believed that a concentration of theone or more retarder compounds greater than 5 wt. % may result ingelation of the acidizing retarder composition, which may reduce theproduction of wormholes, conductive fractures, or combinations thereofin the carbonate formation.

In one or more embodiments, the acidizing retarder composition maycomprise a strong acid. In one or more embodiments, the strong acid ishydrochloric acid. In one or more embodiments, the strong acid maycomprise hydrochloric acid. In one or more embodiments, the strong acidmay comprise hydrochloric acid, nitric acid, sulfuric acid, hydrobromicacid, hydroiodic acid, triflic acid, perchloric acid, or a combinationof two or more thereof. In one or more embodiments, the strong acid isselected from the group consisting of hydrochloric acid, nitric acid,sulfuric acid, hydrobromic acid, hydroiodic acid, triflic acid,perchloric acid, and a combination of two or more thereof. In one ormore embodiments, the strong acid may comprise a mineral acid. In one ormore embodiments, the strong acid may comprise an organic acid. In oneor more embodiments, the strong acid may comprise a mineral acid and anorganic acid.

In one or more embodiments, the acidizing retarder composition maycomprise from 1 wt. % to 40 wt. % of strong acid based on the totalweight of the acidizing retarder composition. For instance, theacidizing retarder composition may comprise from 1 wt. % to 5 wt. %,from 1 wt. % to 10 wt. %, from 1 wt. % to 15 wt. %, from 1 wt. % to 20wt. %, from 1 wt. % to 25 wt. %, from 1 wt. % to 30 wt. %, from 1 wt. %to 35 wt. %, from 1 wt. % to 40 wt. %, from 5 wt. % to 10 wt. %, from 5wt. % to 15 wt. %, from 5 wt. % to 20 wt. %, from 5 wt. % to 25 wt. %,from 5 wt. % to 30 wt. %, from 5 wt. % to 35 wt. %, from 5 wt. % to 40wt. %, from 10 wt. % to 15 wt. %, from 10 wt. % to 20 wt. %, from 10 wt.% to 25 wt. %, from 10 wt. % to 30 wt. %, from 10 wt. % to 35 wt. %,from 10 wt. % to 40 wt. %, from 15 wt. % to 20 wt. %, from 15 wt. % to25 wt. %, from 15 wt. % to 30 wt. %, from 15 wt. % to 35 wt. %, from 15wt. % to 40 wt. %, from 20 wt. % to 25 wt. %, from 20 wt. % to 30 wt. %,from 20 wt. % to 35 wt. %, from 20 wt. % to 40 wt. %, from 25 wt. % to30 wt. %, from 25 wt. % to 35 wt. %, from 25 wt. % to 40 wt. %, from 30wt. % to 35 wt. %, from 30 wt. % to 40 wt. %, or from 35 wt. % to 40 wt.% of strong acid. Without being bound by any particular theory, it isbelieved that a higher concentration of strong acid in the acidizingretarder composition may result in a faster rate of carbonatedissolution. For instance, it is believed that a concentration of strongacid less than 1 wt. % may result in insufficient carbonate dissolution.Further, it is believed that a concentration of strong acid greater than40 wt. % may result in premature carbonate dissolution that may occurnear the surface of the carbonate formation, which may result in moreshallow wormholes, conductive fractures, or combinations thereof.Additionally, a concentration of strong acid greater than 40 wt. % mayincrease the corrosion rate.

In one or more embodiments, the acidizing retarder composition maycomprise 5 wt. % or greater of the strong acid based on the total weightof the acidizing retarder composition. For instance, the acidizingretarder composition may comprise 5 wt. % or greater, 6 wt. % orgreater, 7 wt. % or greater, 8 wt. % or greater, 9 wt. % or greater, 10wt. % or greater, 11 wt. % or greater, 12 wt. % or greater, 13 wt. % orgreater, 14 wt. % or greater, or 15 wt. % or greater of the strong acid.

In one or more embodiments, the acidizing retarder composition maycomprise one or more corrosion inhibitors. As used herein, the term“corrosion inhibitor” may refer to chemical compound, material, ormixture that, when added to a fluid, decreases the corrosion rate ofmaterial that comes into contact with the fluid. In one or moreembodiments, the acidizing retarder composition may comprise from 0.01wt. % to 5 wt. % of corrosion inhibitors based on the total weight ofthe acidizing retarder composition. For instance, the acidizing retardercomposition may comprise from 0.01 wt. % to 0.5 wt. %, 0.01 wt. % to 1wt. %, from 0.01 wt. % to 2 wt. %, from 0.01 wt. % to 3 wt. %, from 0.01wt. % to 4 wt. %, from 0.01 wt. % to 5 wt. %, from 0.5 wt. % to 1 wt. %,from 0.5 wt. % to 2 wt. %, from 0.5 wt. % to 3 wt. %, from 0.5 wt. % to4 wt. %, from 0.5 wt. % to 5 wt. %, from 1 wt. % to 2 wt. %, from 1 wt.% to 3 wt. %, from 1 wt. % to 4 wt. %, or from 1 wt. % to 5 wt. % ofcorrosion inhibitors. Without intending to be bound by any particulartheory, it is believed that a concentration of corrosion inhibitorsbelow 0.01 wt. % may result in insufficient reduction of corrosion.Further, it is believed that a concentration of corrosion inhibitorsgreater than 5 wt. % may result in the plugging of porous media in theformation, which may cause formation damage. The maximum acceptablecorrosion inhibitor concentration may be determined by corrosion testsand the formation damage tendency, which may be obtained by corefloodingexperiments.

In one or more embodiments, the acidizing retarder composition maycomprise one or more additives, including but not limited to solvents,foaming agents, gelling agents, iron control agents or H₂S scavengers.

In acid stimulation treatments, the acid present in the acidizingretarder composition may react with minerals within the subterraneanformation to improve the permeability and enable the enhanced productionof fluids. In one or more embodiments, the acidizing retardercomposition dissolves minerals within the subterranean formation tostimulate the subterranean formation and increase hydrocarbonproduction.

In subterranean formations that comprise carbonate, the acid maydissolve the entire formation matrix. As such, in some embodiments, theminerals dissolved within the subterranean formation may comprisecalcite (CaCO₃). In other embodiments, the minerals dissolved within thesubterranean formation may comprise dolomite (CaMg(CO₃)₂). In otherembodiments, the minerals dissolved within the subterranean formationmay comprise both calcite and dolomite.

In one or more embodiments, the acidizing retarder composition may beintroduced into the subterranean formation. The acid present in theacidizing retarder composition may penetrate the formation and extendthe depth of the carbonate acidizing treatment while avoiding damage tothe formation.

In one or more embodiments, one or more retarder compounds may bedissolved in a solution comprising a strong acid to form an acidizingretarder composition. In one or more embodiments, at least one of theone or more retarder compounds may comprise a poloxamer.

In one or more embodiments, the acidizing retarder composition may beintroduced to the carbonate formation. The acidizing retardercomposition may be introduced to the carbonate formation through tubing,including but not limited to, coiled tubing, production tubing,bullheading, or combinations thereof. The acidizing retarder compositionmay be mixed in one or more batch mixers at the surface of thereservoir. The acidizing retarder composition may then be injected intothe reservoir.

In one or more embodiments, the rate of carbonate dissolution in thepresence of the acidizing retarder composition may be reduced by a rangefrom 5% to 95%, relative to a rate of carbonate dissolution in theabsence of the acidizing retarder composition. For instance, in someembodiments, the rate of carbonate dissolution in the presence of theacidizing retarder composition may be reduced by a range from 5% to 10%,from 5% to 25%, from 5% to 50%, from 5% to 75%, from 5% to 95%, from 25%to 50%, from 25% to 75%, from 25% to 95%, from 50% to 75%, from 50% to95%, or from 75% to 95%. Without intending to be bound by any particulartheory, it is believed that a reduction in the rate of carbonatedissolution may result in deeper acid penetration in a carbonatereservoir, which may increase hydrocarbon production.

In one or more embodiments, wormholes, conductive fractures, orcombinations thereof may be formed in the carbonate formation. As usedherein, “wormholes” may refer to an empty channel that may penetrateinto the formation that form upon acid dissolution. As used herein,“conductive fractures” may refer to fractures formed when a stimulationfluid is injected at a pressure greater than the fracture pressure,which may result in the formation of fractures and a reaction betweenthe acid and rock to keep the fracture conductive.

In one or more embodiments, the carbonate formation may be in areservoir comprising hydrocarbons. In one or more embodiments, thehydrocarbons may be extracted from the reservoir.

Advantages of some embodiments disclosed herein may include, but are notlimited to, improved acid stimulation, increased hydrocarbon production,and reduced acid volume required for acid stimulation.

According to an aspect, either alone or in combination with any otheraspect, a method of reducing a rate of carbonate dissolution in acarbonate acidizing treatment of a carbonate formation comprisesdissolving one or more retarder compounds in a solution comprising astrong acid to form an acidizing retarder composition and introducingthe acidizing retarder composition to the carbonate formation. At leastone of the one or more retarder compounds comprises a poloxamer.

According to a second aspect, either alone or in combination with anyother aspect, the poloxamer comprises a compound of formula (I):

in which x and z are each independently an integer from 50 to 150, andin which y is an integer from 20 to 80.

According to a third aspect, either alone or in combination with anyother aspect, x and z are each independently an integer from 95 to 105,and y is an integer from 50 to 60.

According to a fourth aspect, either alone or in combination with anyother aspect, the strong acid comprises hydrochloric acid, nitric acid,sulfuric acid, hydrobromic acid, hydroiodic acid, triflic acid,perchloric acid, or a combination of two or more thereof.

According to a fifth aspect, either alone or in combination with anyother aspect, the acidizing retarder composition comprises from 0.1weight percent to 5 weight percent of the one or more retarder compoundsbased on the total weight of the acidizing retarder composition.

According to a sixth aspect, either alone or in combination with anyother aspect, the acidizing retarder composition comprises from 5 weightpercent to 30 weight percent of the strong acid based on the totalweight of the acidizing retarder composition.

According to a seventh aspect, either alone or in combination with anyother aspect, the acidizing retarder composition comprises greater than5 weight percent of the strong acid based on the total weight of theacidizing retarder composition.

According to an eighth aspect, either alone or in combination with anyother aspect, the acidizing retarder composition further comprises oneor more corrosion inhibitors.

According to a ninth aspect, either alone or in combination with anyother aspect, the acidizing retarder composition comprises from 0.01weight percent to 5 weight percent of the one or more corrosioninhibitors based on the total weight of the acidizing retardercomposition.

According to a tenth aspect, either alone or in combination with anyother aspect, the method further comprises forming wormholes, conductivefractures, or combinations thereof, in the carbonate formation duringthe carbonate acidizing treatment.

According to an eleventh aspect, either alone or in combination with anyother aspect, the carbonate formation is in a reservoir comprisinghydrocarbons.

According to a twelfth aspect, either alone or in combination with anyother aspect, the carbonate formation is in a reservoir comprisinghydrocarbons, and the method further comprises extracting thehydrocarbons from the reservoir.

According to a thirteenth aspect, either alone or in combination withany other aspect, an acidizing retarder composition comprises one ormore retarder compounds and a strong acid. At least one of the one ormore retarder compounds is a poloxamer. A concentration of the strongacid in the acidizing retarder composition is 5 weight percent orgreater.

According to a fourteenth aspect, either alone or in combination withany other aspect, the poloxamer comprises a compound of formula (I):

in which x and z are each independently an integer from 50 to 150, andin which y is an integer from 20 to 80.

According to a fifteenth aspect, either alone or in combination with anyother aspect, x and z are each independently an integer from 95 to 105,and y is an integer from 50 to 60.

According to a sixteenth aspect, either alone or in combination with anyother aspect, the strong acid comprises hydrochloric acid, nitric acid,sulfuric acid, hydrobromic acid, hydroiodic acid, triflic acid,perchloric acid, or a combination of two or more thereof.

According to a seventeenth aspect, either alone or in combination withany other aspect, the acidizing retarder composition comprises from 0.1weight percent to 5 weight percent of the one or more retarder compoundsbased on the total weight of the acidizing retarder composition.

According to an eighteenth aspect, either alone or in combination withany other aspect, the acidizing retarder composition comprises from 5weight percent to 30 weight percent of the strong acid based on thetotal weight of the acidizing retarder composition.

According to a nineteenth aspect, either alone or in combination withany other aspect, the acidizing retarder composition further comprisesone or more corrosion inhibitors.

According to a twentieth aspect, either alone or in combination with anyother aspect, the acidizing retarder composition comprises from 0.01weight percent to 5 weight percent of the one or more corrosioninhibitors based on the total weight of the acidizing retardercomposition.

EXAMPLES

The various embodiments disclosed herein will be further clarified bythe following examples. The examples are illustrative in nature, andshould not be understood to limit the embodiments disclosed herein.Acidizing retarder compositions are prepared and reacted with calciumcarbonate discs to demonstrate a reduced rate of carbonate dissolution.

Example 1. Reduced Carbonate Dissolution Using Acidizing RetarderCompositions at 65° C.

Acidizing retarder compositions are prepared by dissolving a retardercompound in HCl according to Table 1, where the weight percent (wt. %)of HCl and the retarder compound is the wt. % of the prepared acidizingretarder composition before combining with the calcium carbonate discand the balance is water. The retarder compound used in the Examples isPoloxamer 407, a triblock copolymer commercially available as Pluronic™F-127 from BASF. Additionally, comparative Example 1 is prepared using15 wt. % HCl in the absence of a retarder compound. A 10 mL sample ofeach acidizing retarder composition and the comparative example is thenplaced in a separate glass bottle and heated in an oven at 65° C. for 10minutes. Each carbonate disc is weighed and then heated in the oven at65° C. for 10 minutes. The carbonate disc is then dropped in each glassbottle and an acid-carbonate reaction initiates. After 20 minutes, eachglass bottle is removed from the oven and the reaction is quenched byadding approximately 2 liters (L) of cold deionized (DI) water to eachglass bottle. The solid unreacted calcium carbonate discs are removedfrom each bottle, dried, and weighed. The mass of each carbonate discbefore the reaction (initial), the mass of each carbonate disc afterreacting for 20 minutes, the mass loss, and the dissolution rate foreach Example is reported in Table 1. As seen in Table 1, the addition ofPoloxamer 407 in Examples 1-1, 1-2, and 1-3 results in a considerablyslower carbonate dissolution rate in relation to Comparative Example 1,which does not comprise a retarder compound.

TABLE 1 Initial Carbonate Wt. % carbonate disc mass Mass Dissolution Wt.% retarder disc after 20 loss rate Example HCI compound mass (g) min.(g) (g) (g/min) Comparative 15 0 3.85 1.4154 2.4346 0.1217 Example 1Example 1-1 15 0.5 3.31 2.1803 1.1297 0.0565 Example 1-2 15 1.0 3.292.1196 1.1704 0.0585 Example 1-3 15 5.0 3.05 2.2463 0.8037 0.0402

Example 2. Reduced Carbonate Dissolution Using Acidizing RetarderCompositions at 85° C.

An acidizing retarder composition is prepared by dissolving a retardercompound in HCl according to Table 2, where the weight percent (wt. %)of HCl and the retarder compound is the wt. % of the prepared acidizingretarder composition before combining with the calcium carbonate disc,and the balance is water. Additionally, Comparative Example 2 isprepared using 15 wt. % HCl in the absence of a retarder compound. A 15mL sample of the acidizing retarder composition and the comparativeexample is then placed in a separate glass bottle and heated in an ovenat 85° C. for 10 minutes. Each carbonate disc is weighed and then heatedin the oven at 85° C. for 10 minutes. The carbonate disc is then droppedin each glass bottle and an acid-carbonate reaction initiates. After 5minutes, each glass bottle is removed from the oven and the reaction isquenched by adding approximately 2 L of cold DI water to each glassbottle. The solid unreacted calcium carbonate discs are removed fromeach bottle, dried, and weighed. The mass of each carbonate disc beforethe reaction (initial), the mass of each carbonate disc after reactingfor 5 minutes, the mass loss, and the dissolution rate for each Exampleis reported in Table 2. As seen in Table 2, the addition of Poloxamer407 in Example 2-1, results in a considerably slower carbonatedissolution rate in relation to Comparative Example 2, which does notcomprise a retarder compound.

TABLE 2 Initial Carbonate Wt. % carbonate disc mass Mass Dissolution Wt.% retarder disc after 5 loss rate Example HCI compound mass (g) min. (g)(g) (g/min) Comparative 15 0 5.99 2.7496 3.2367 0.1618 Example 2 Example2-1 15 1.0 5.21 4.5633 0.6475 0.0324

Example 3. Reduced Carbonate Dissolution Using Acidizing RetarderCompositions Comprising a Corrosion Inhibitor at 85° C.

An acidizing retarder composition is prepared by dissolving a retardercompound and a corrosion inhibitor in HCl according to Table 3, wherethe weight percent (wt. %) of HCl, the retarder compound, and thecorrosion inhibitor is the wt. % relative to the weight of the preparedacidizing retarder composition before combining with the calciumcarbonate disc, and the balance is water. Additionally, ComparativeExample 3 is prepared using 15 wt. % HCl and 1 wt. % corrosion inhibitorin the absence of a retarder compound. The corrosion inhibitor used isBASFCorr from BASF. A 15 mL sample of the acidizing retarder compositionand the comparative example is then placed in a separate glass bottleand heated in an oven at 85° C. for 10 minutes. Each carbonate disc isweighed and then heated in the oven at 85° C. for 10 minutes. Thecarbonate disc is then dropped in each glass bottle and anacid-carbonate reaction initiates. After 5 minutes, each glass bottle isremoved from the oven and the reaction is quenched by addingapproximately 2 L of cold DI water to each glass bottle. The solidunreacted calcium carbonate discs are removed from each bottle, dried,and weighed. The mass of each carbonate disc before the reaction(initial), the mass of each carbonate disc after reacting for 5 minutes,the mass loss, and the dissolution rate for each Example is reported inTable 3. As seen in Table 3, the addition of Poloxamer 407 in Example3-1, which comprises a retarder compound and a corrosion inhibitor,results in a considerably slower carbonate dissolution rate in relationto Comparative Example 3, which comprises a corrosion inhibitor but doesnot comprise a retarder compound.

TABLE 3 Initial Carbonate Wt. % Wt. % carbonate disc mass MassDissolution Wt. % retarder Corrosion disc after 5 loss rate Example HCIcompound inhibitor mass (g) min. (g) (g) (g/min) Comparative 15 0 1.06.73 3.7045 3.0294 0.1515 Example 3 Example 3-1 15 1.0 1.0 5.08 4.50440.5735 0.0287

It will be apparent to persons of ordinary skill in the art that variousmodifications and variations can be made without departing from thescope disclosed herein. Since modifications, combinations,sub-combinations, and variations of the disclosed embodiments, whichincorporate the spirit and substance disclosed herein, may occur topersons of ordinary skill in the art, the scope disclosed herein shouldbe construed to include everything within the scope of the appendedclaims and their equivalents.

It is noted that one or more of the following claims utilize the term“where” or “in which” as a transitional phrase. For the purposes ofdefining the present technology, it is noted that this term isintroduced in the claims as an open-ended transitional phrase that isused to introduce a recitation of a series of characteristics of thestructure and should be interpreted in like manner as the more commonlyused open-ended preamble term “comprising.” For the purposes of definingthe present technology, the transitional phrase “consisting of” may beintroduced in the claims as a closed preamble term limiting the scope ofthe claims to the recited components or steps and any naturallyoccurring impurities. For the purposes of defining the presenttechnology, the transitional phrase “consisting essentially of” may beintroduced in the claims to limit the scope of one or more claims to therecited elements, components, materials, or method steps as well as anynon-recited elements, components, materials, or method steps that do notmaterially affect the novel characteristics of the claimed subjectmatter. The transitional phrases “consisting of” and “consistingessentially of” may be interpreted to be subsets of the open-endedtransitional phrases, such as “comprising” and “including,” such thatany use of an open ended phrase to introduce a recitation of a series ofelements, components, materials, or steps should be interpreted to alsodisclose recitation of the series of elements, components, materials, orsteps using the closed terms “consisting of” and “consisting essentiallyof.” For example, the recitation of a composition “comprising”components A, B, and C should be interpreted as also disclosing acomposition “consisting of” components A, B, and C as well as acomposition “consisting essentially of” components A, B, and C. Anyquantitative value expressed in the present application may beconsidered to include open-ended embodiments consistent with thetransitional phrases “comprising” or “including” as well as closed orpartially closed embodiments consistent with the transitional phrases“consisting of” and “consisting essentially of.”

As used in the Specification and appended Claims, the singular forms“a”, “an”, and “the” include plural references unless the contextclearly indicates otherwise. The verb “comprises” and its conjugatedforms should be interpreted as referring to elements, components orsteps in a non-exclusive manner. The referenced elements, components orsteps may be present, utilized or combined with other elements,components or steps not expressly referenced.

It should be understood that any two quantitative values assigned to aproperty may constitute a range of that property, and all combinationsof ranges formed from all stated quantitative values of a given propertyare contemplated in this disclosure. The subject matter disclosed hereinhas been described in detail and by reference to specific embodiments.It should be understood that any detailed description of a component orfeature of an embodiment does not necessarily imply that the componentor feature is essential to the particular embodiment or to any otherembodiment. Further, it should be apparent to those skilled in the artthat various modifications and variations can be made to the describedembodiments without departing from the spirit and scope of the claimedsubject matter.

1. A method of reducing a rate of carbonate dissolution in a carbonateacidizing treatment of a carbonate formation, the method comprising:dissolving one or more retarder compounds in a solution comprising acidto form an acidizing retarder composition, wherein the acid consists ofstrong mineral acid, wherein at least one of the one or more retardercompounds comprises a poloxamer, and wherein the acidizing retardercomposition comprises from 0.5 weight percent to 5 weight percent of theone or more retarder compounds based on the total weight of theacidizing retarder composition; and introducing the acidizing retardercomposition to the carbonate formation, wherein the rate of carbonatedissolution in the presence of the acidizing retarder composition isreduced by an amount of from 50% to 95%, relative to a rate of carbonatedissolution in the absence of the acidizing retarder composition.
 2. Themethod of claim 1, wherein the poloxamer comprises a compound of formula(I):

in which x and z are each independently an integer from 50 to 150; andin which y is an integer from 20 to
 80. 3. The method of claim 2,wherein x and z are each independently an integer from 95 to 105; and yis an integer from 50 to
 60. 4. The method of claim 1, wherein thestrong mineral acid comprises hydrochloric acid, nitric acid, sulfuricacid, hydrobromic acid, hydroiodic acid, triflic acid, perchloric acid,or a combination of two or more thereof.
 5. (canceled)
 6. (canceled) 7.The method of claim 1, wherein the acidizing retarder compositioncomprises greater than 5 weight percent of the acid based on the totalweight of the acidizing retarder composition.
 8. The method of claim 1,wherein the acidizing retarder composition further comprises one or morecorrosion inhibitors.
 9. The method of claim 8, wherein the acidizingretarder composition comprises from 0.01 weight percent to 5 weightpercent of the one or more corrosion inhibitors based on a total weightof the acidizing retarder composition.
 10. The method of claim 1,further comprising forming wormholes, conductive fractures, orcombinations thereof, in the carbonate formation during a carbonateacidizing treatment.
 11. The method of claim 1, wherein the carbonateformation is in a reservoir comprising hydrocarbons.
 12. The method ofclaim 1, wherein the carbonate formation is in a reservoir comprisinghydrocarbons, and the method further comprises extracting thehydrocarbons from the reservoir.
 13. An acidizing retarder compositioncomprising: one or more retarder compounds; and an acid, wherein theacid consists of a strong mineral acid; wherein at least one of the oneor more retarder compounds is a poloxamer; and wherein a concentrationof the acid in the acidizing retarder composition is 5 weight percent orgreater.
 14. The acidizing retarder composition of claim 13, wherein thepoloxamer comprises a compound of formula (I):

in which x and z are each independently an integer from 50 to 150; andin which y is an integer from 20 to
 80. 15. The acidizing retardercomposition of claim 14, wherein x and z are each independently aninteger from 95 to 105; and y is an integer from 50 to
 60. 16. Theacidizing retarder composition of claim 13, wherein the mineral acidcomprises hydrochloric acid, nitric acid, sulfuric acid, hydrobromicacid, hydroiodic acid, triflic acid, perchloric acid, or a combinationof two or more thereof.
 17. The acidizing retarder composition of claim13, wherein the acidizing retarder composition comprises from 0.1 weightpercent to 5 weight percent of the one or more retarder compounds basedon the total weight of the acidizing retarder composition.
 18. Theacidizing retarder composition of claim 13, wherein the acidizingretarder composition comprises from 5 weight percent to 30 weightpercent of the acid based on the total weight of the acidizing retardercomposition.
 19. The acidizing retarder composition of claim 13, whereinthe acidizing retarder composition further comprises from 0.01 weightpercent to 5 weight percent of one or more corrosion inhibitors. 20.(canceled)
 21. The method of claim 1, wherein the acidizing retardercomposition does not comprise a corrosion inhibitor; or wherein theacidizing retarder composition comprises only one corrosion inhibitor.22. The method of claim 1, wherein the acidizing retarder compositionconsists of water, the strong acid, the one or more retarder compoundsand, optionally, one corrosion inhibitor.
 23. (canceled)
 24. A method ofreducing a rate of carbonate dissolution in a carbonate acidizingtreatment of a carbonate formation, the method comprising: dissolvingone or more retarder compounds in a solution comprising a strong acid toform an acidizing retarder composition, wherein at least one of the oneor more retarder compounds comprises a poloxamer, and wherein theacidizing retarder composition comprises from 0.5 weight percent to 5weight percent of the one or more retarder compounds based on the totalweight of the acidizing retarder composition; and introducing theacidizing retarder composition to the carbonate formation, wherein therate of carbonate dissolution in the presence of the acidizing retardercomposition is reduced by an amount of from 50% to 95%, relative to arate of carbonate dissolution in the absence of the acidizing retardercomposition; wherein the poloxamer comprises a compound of formula (I):

in which x and z are each independently an integer from 50 to 150; andin which y is an integer from 20 to 80.